1. Field of the Invention
The present invention relates to an integrated material comprising reagent layer units for chemical analysis and a method of using the same. More particularly, the present invention relates to a material capable of performing a plurality of chemical analyses at one time. Still more particularly, the present invention relates to an integrated material in which a plurality of units containing different reagents for chemical analysis are proximately arranged on a support so that at least a portion of their reagent layer units are in contact with each other or in close vicinity to one another within a spreading circle defined by the diffusion of an assay sample as it passes through a porous spreading layer.
2. Description of the Prior Art
As materials for simple and rapid dry chemical analyses of liquid samples, sheet-like multilayered materials for chemical analysis have been disclosed in U.S. Pat. Nos. 3,526,480, 3,663,374, 3,992,158, 4,042,355, 4,066,403 and 4,050,898 and collected papers (pp. 13, 14, 47, 76 and 118) for the 10th International Conference of Clinical Chemistry (Mexico City, 2/26-3/3/78). Such multilayered materials for chemical analysis are based on the idea of providing a thin film containing a reagent for the analysis in a binder such as gelatin beforehand, and on chemical analysis a drop of liquid sample to be tested is applied to the sheet. The reagent layer contains a system which, upon reacting with a particular component in the sample liquid, leads to color development, coloration or discoloration. The content of the particular component in the sample liquid corresponds to the color density and quantitative analysis is possible by optical analysis chiefly by colorimetry. Unlike the conventional methods, these materials are dry materials for chemical analysis and eliminate the need for reagent solutions and test tubes.
The fundamental construction of these multilayered materials for chemical analysis is a combination of a porous spreading layer and a reagent layer, and the reagent layer is sometimes provided as a multilayered unit by dividing its functions between, for example, a first reagent layer and a second reagent layer or between a reagent layer and a color developing, a color detecting or a color receiving layer. Sometimes an intermediate layer such as a radiation-blocking layer or a barrier layer is placed between such a plurality of the reagent layers. Alternatively, there is provided a construction in which the spreading layer includes a reagent and spreading and the reaction upon which the analysis is based are integrated. In any case, it is basic that the layer construction comprises two functional layers, i.e., a spreading layer and a reagent layer. A liquid sample dropped on such a multilayered material for chemical analysis diffuses uniformly throughout the porous spreading layer and permeates into the reagent layer when it reacts with the reagents contained therein.
The above-mentioned multilayered materials for chemical analysis are very suitable for a simple and rapid chemical assay of liquid samples containing many components such as saliva, blood, urine, etc., in a dry state operation using no test tubes or reagent solutions. Such a material requires analytical reagents for the specific items to be analyzed, for example, reagents for the quantitative assay of blood for glucose, urea nitrogen and amylase. Therefore, when six times, e.g., bilirubin, albumin and cholesterol in addition to the above three are to be quantitatively analyzed, it is necessary to choose six different multilayered materials for each chemical analysis and to apply a drop of whole blood or serum in an amount of 5 to 15 .mu.l on each material, after which, upon completion of each color development reaction, colorimetric analyses of the respective materials are conducted.
The above-mentioned multilayered materials for chemical analysis are quite excellent with respect to the simplicity of the quantitative analysis, and when used for the purpose of the chemical analysis of blood, these materials are very convenient for analyzing one item per patient. However, it is common practice in clinical chemistry examinations to test 5 to 10 items on each blood sample collected from each patient. Therefore, in order to utilize the above-mentioned multilayered materials for the chemical analysis for that purpose, there is involved the relatively complicated procedure of choosing an analytical material for each of the 5 to 10 items tested, number them and apply a drop of the blood on each material. Further, when conducting tests on many persons (as would be the case in a hospital), selection of the analytical materials, numbering, repetition of application, etc., amount to an enormous amount of work. In this respect, efforts have been made to minimize the number of such repetitions and it has been discovered that by using an integrated material constructed such that the necessary number of reagents for each chemical analysis are incorporated in a specific arrangement, e.g., radially on a support, and applying the sample to be tested at a centrally located point such that the sample diffuses to each analytical material, the analysis is simplified.